Ovarian cancer risk and oestrogen

The oestrogen component of oral hormone replacement therapy around the time of menopause is associated with ovarian cancer risk. It has long been known that hormone replacement therapy is a risk factor for breast and endometrial cancer, as well as coronary heart disease and stroke, but the association with ovarian cancer is less clear. Researchers from the Danish Cancer Society in Copenhagen, Denmark, analysed hormone therapy use in 376 ovarian cancer patients between the ages of 35 and 79, who had not undergone hysterectomy and 1111 healthy women of the same age. The cumulative intake of oestrogen among women who had ever used oral hormone therapy ranged between 0.04 to 41.1 grams. Higher cumulative oral intake of oestrogen significantly raised the risk of ovarian cancer, the researchers found. They observed a simple trend such that each additional gram of oestrogen was associated with the same relative increase in risk of ovarian cancer. After accounting for established risk factors, it was found that this corresponded to a 31 percent greater risk for every 5 grams of oestrogen. The risk of ovarian cancer did not increase with the duration or the cumulative intake of progestogen component of hormone therapy.  The study suggests that the increased ovarian cancer risk associated with oral hormone therapy may be diminished substantially by minimising the daily dose of oestrogen from oral hormone therapy.

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